Grant Stephens Print




:  Heliophysics


Degree Field of Study Year Attained Institution Name
B.S. Astronomy and Astrophysics 2009 Penn State
B.S. Physics 2009 Penn State
M.S. Applied Physics 2013 Johns Hopkins

The Earth’s magnetic field forms a protective cocoon from the solar wind called the magnetosphere. The magnetosphere is not a static structure and reacts to changes in the solar wind. For example, the Sun will occasionally emit a large bundle of magnetized plasma termed a coronal mass ejection or CME. When a CME sweeps past the Earth it can trigger a large magnetic disturbance throughout the magnetosphere called a geomagnetic storm. Another type of disturbance, substorms, occurs when a large amount of magnetic energy is stored on the nightside of the Earth which is suddenly released, accelerating particles toward the poles and lighting the night sky with the aurora. Both storms and substorms are important aspects of space weather and can have profound impacts on both spacecraft and astronauts. Grant Stephens’ research involves describing these events using data-driven models of the magnetosphere’s magnetic field and electric current systems. He employs data-mining methods to extract information on the dynamics of these systems from decades of spacecraft magnetometer measurements which then gets ingested into the model, forming a global picture of storms and substorms. Additionally, Grant has developed similar models for other planets such as Mercury and Saturn.

AGU Index Category AGU Index Sub-Category
MAGNETOSPHERIC PHYSICS Magnetic storms and substorms
MAGNETOSPHERIC PHYSICS Magnetospheric configuration and dynamics
MAGNETOSPHERIC PHYSICS Planetary magnetospheres
SPACE WEATHER Magnetic storms
Start Year End Year Description
2010 Current Scientific Modeling and Analysis - Johns Hopkins Applied Physics Lab
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Drew L. Turner, Ian J. Cohen, Samuel T. Bingham, Grant K. Stephens, Mikhail I. Sitnov, Barry H. Mauk, Richard E. Denton, Trevor W. Leonard, Joseph F. Fennell, J. Bernard Blake, Roy B. Torbert, James L. Burch, (2021), Characteristics of Energetic Electrons Near Active Magnetotail Reconnection Sites: Tracers of a Complex Magnetic Topology and Evidence of Localized Acceleration, Geophysical Research Letters , 48, 2,

N. A. Tsyganenko, V. A. Andreeva, M. I. Sitnov, G. K. Stephens, J. W. Gjerloev, X. Chu, O. A. Troshichev, (2021), Reconstructing substorms via historical data mining: Is it really feasible?, Journal of Geophysical Research: Space Physics ,

M. I. Sitnov, G. K. Stephens, N. A. Tsyganenko, H. Korth, E. C. Roelof, P. C. Brandt, V. G. Merkin, A. Y. Ukhorskiy, (2020), Reconstruction of Extreme Geomagnetic Storms: Breaking the Data Paucity Curse, Space Weather , 18, 10,

G. K. Stephens, S. T. Bingham, M. I. Sitnov, M. Gkioulidou, V. G. Merkin, H. Korth, N. A. Tsyganenko, A. Y. Ukhorskiy, (2020), Storm Time Plasma Pressure Inferred From Multimission Measurements and Its Validation Using Van Allen Probes Particle Data, Space Weather , 18, 12,

G. K. Stephens, M. I. Sitnov, H. Korth, N. A. Tsyganenko, S. Ohtani, M. Gkioulidou, A. Y. Ukhorskiy, (2019), Global Empirical Picture of Magnetospheric Substorms Inferred From Multimission Magnetometer Data, Journal of Geophysical Research: Space Physics , 124, 2, 1085--1110,

M. I. Sitnov, G. K. Stephens, N. A. Tsyganenko, Y. Miyashita, V. G. Merkin, T. Motoba, S. Ohtani, K. J. Genestreti, (2019), Signatures of Nonideal Plasma Evolution During Substorms Obtained by Mining Multimission Magnetometer Data, Journal of Geophysical Research: Space Physics , 124, 11, 8427--8456,

Brett W. Denevi, Nancy L. Chabot, Scott L. Murchie, Kris J. Becker, David T. Blewett, Deborah L. Domingue, Carolyn M. Ernst, Christopher D. Hash, S. Edward Hawkins, Mary R. Keller, Nori R. Laslo, Hari Nair, Mark S. Robinson, Frank P. Seelos, Grant K. Stephens, F. Scott Turner, Sean C. Solomon, (2018), Calibration, Projection, and Final Image Products of MESSENGER's Mercury Dual Imaging System, Space Science Reviews, 214, 1

M. Wiltberger, V. Merkin, B. Zhang, F. Toffoletto, M. Oppenheim, W. Wang, J. G. Lyon, J. Liu, Y. Dimant, M. I. Sitnov, G. K. Stephens, (2017), Effects of electrojet turbulence on a magnetosphere-ionosphere simulation of a geomagnetic storm, Journal of Geophysical Research-Space Physics, 122, 5, 5008-5027

Mikhail I. Sitnov, Grant K. Stephens, Nikolai A. Tsyganenko, Aleksandr Y. Ukhorskiy, Simon Wing, Haje Korth, Brian J. Anderson, (2017), Spatial Structure and Asymmetries of Magnetospheric Currents Inferred from High-Resolution Empirical Geomagnetic Field Models, Dawn-Dusk Asymmetries in Planetary Plasma Environments, 230 , 199-212

Scott L. Murchie, Hari Nair, Grant K. Stephens, (2016), Determining shape of a seasonally shadowed asteroid using stellar occultation imaging, Planetary and Space Science, 131, 24-32

G. K. Stephens, M. I. Sitnov, A. Y. Ukhorskiy, E. C. Roelof, N. A. Tsyganenko, G. Le, (2016), Empirical modeling of the storm time innermost magnetosphere using Van Allen Probes and THEMIS data: Eastward and banana currents, Journal of Geophysical Research-Space Physics, 121, 1, 157-170

G. K. Stephens, M. I. Sitnov, J. Kissinger, N. A. Tsyganenko, R. L. McPherron, H. Korth, B. J. Anderson, (2013), Empirical reconstruction of storm time steady magnetospheric convection events, Journal of Geophysical Research-Space Physics, 118, 10, 6434-6456

M. I. Sitnov, A. Y. Ukhorskiy, G. K. Stephens, (2012), Forecasting of global data-binning parameters for high-resolution empirical geomagnetic field models, Space Weather-the International Journal of Research and Applications, 10